1. Field of the Invention
This invention relates to an electric circuit apparatus, and more specifically to an electric circuit apparatus wherein a circuit board, on which electronic and/or electric parts are attached and in which an electric circuit connected to the parts is mounted, is contained in a long and narrow case having two openings at both ends thereof, and a pair of terminal bases including at least one external terminal is provided at the two openings within the case.
2. Description of the Related Art
As such electric circuit apparatus, for instance, an electric discharge lamp stabilizer used for lighting and operating a discharge lamp such as a fluorescent lamp is well known.
As shown in FIG. 1, the conventional electronic discharge lamp stabilizer comprises case 10 shaped in a rectangular pipe and constructed by cover 10A and main body 10B which are removable upwardly and downwardly. Main body 10B has a pair of side board portions 10b which are downwardly extending substantially parallel with each other from both longitudinally extending side edges of main board portion 10a shaped in an rectangle. In both longitudinal ends of main board portion 10a, through holes 10c are formed for fixing main body 10B by means of a publicly known fixing means such as screws for instance to a chassis of lighting equipment such as a fluorscent lamp (not shown).
Between the pair of side board portions 10b, a long and narrow electric circuit board 12 extending along main board portion 10a is disposed. Electric circuit board 12 is screwed to radiating board 14 which is screwed to one side board portion 10b of main body 10B. A predetermined wiring is printed on a surface of electric circuit board 12 facing the lower opening of main body 10B, and connecting terminals 17 of, for instance, transforms 16a as an inverter element having a core, switching transistor 16b used as a switching element and closely contacted onto radiating board 14, and other various electronic and/or electric parts 16c, are passing through and soldered to predetermined positions of the wiring, whereby they are electrically connected to the wiring to construct a discharge lamp operating circuit. A plurality of terminal bases 18 having external connecting terminals are attached at both longitudinal ends on a lower surface of electric circuit board 12, and the external connecting terminals of the individual terminal bases 18 are also electrically connected to the predetermined positions of the predetermined wiring on the lower surface of electric circuit board 12. Openings 18a of the external connecting terminals of the individual terminal bases 18 are downwardly facing, the external connecting terminals of one group of terminal bases 18 disposed at one longitudinal end of electric circuit board 12 are used to be connected to a general commercial power supply, and the external connecting terminals of the remaing group of terminal bases 18 disposed at the other longitudinal end of electric circuit board 12 are used to be connected to a fluorescent bulb socket.
Cover 10A also has a pair of side board portions 10d downwardly extending out substantially in parallel with each other from both longitudinally extending side edges of rectangular main board portions 10c.
Engaging holes 20A are formed in a plurality of positions of each of the pair of side board portions 10b of main body 10B so as to be arranged along the longitudinal direction thereof, and engaging protrusions 20B are formed in a plurality of positions of each of the pair of side board portions 10d of cover 10A so as to be arranged along the longitudinal direction thereof.
In order to connect cover 10A to main body 10B, the pair of side board portions 10d of cover 10A are firstly outwardly expanded so as to move them away from each other, and then the pair of side board portions 10d of cover 10A are slipped onto outer surfaces of the pair of side board portions 10b of main body 10B from the lower side thereof. At this time, the expanding force applied on the pair of side board portions 10d is removed, the plurality of engaging protrusions 20B of the pair of side board portions 10d of cover 10A can be made to engage with the plurality of engaging holes 20A of the pair of side board portions 10b of main body 10B, as shown in FIG. 2. This allows cover 10A to be removably coupled with main body 10B and constitute case 10 of a rectangular pipe in conjunct-on with main body 10B.
The wiring work for the conventional electronic discharge lamp stabilizer constructed as described above is performed after the electronic discharge lamp stabilizer is fixed to the chassis of the fluorescent lamp lighting equipment, not shown. In the wiring work, cover 10A is firstly removed from main body 10B, then one ends of the general commercial power supply leads are inserted into openings 18a of the external connecting terminals of terminal bases 18 for power supply connection to be connected to the corresponding external terminals, and one ends of the leads from the fluorescent bulb socket of the fluorescent lamp lighting equipment are inserted into openings 18a of the external connecting terminals of terminal bases 18 for fluorescent lamp connection to be connected to the corresponding external connecting terminals.
Since openings 18a of the external connecting terminals of terminal bases 18 are downwardly facing in the conventional electronic discharge stabilizer constructed as stated above, cover 10A must be removed from main body 10B in the above-mentioned wiring work. In addition, by the same reason, the leads connected to the external connecting terminals of terminal bases 18 must change an extending direction thereof from a downward direction to a horizontal direction as they go away from the external connecting terminals, so that they do not prevent the work of attaching cover 10A to main body 10B after the wiring work is completed.
Accordingly, in order to allow the downward extension of the leads from terminal bases 18 and the subsequent change in the extending direction of the leads, the height of cover 10A must be set so that a sufficient distance can be maintained between circuit board 12 supported by main body 10B and main board portion 10c of cover 10A when cover 10A is attached to main body 10B. This hinders the attempt of reducing the height of the conventional electronic discharge stabilizer, and hence hinders the attempt of reducing the height of the traditional fluorescent lamp lighting equipment.
Moreover, the engaging and disengaging works of cover 10A in regard of main body 10B are combersome in the wiring work